1. Field of the Invention
The present invention relates to the setting of grade stakes and, more particularly, but not in the way of limitation, to an apparatus for driving grade stakes.
2. Description of the Related Art
Most construction projects require the excavation and/or the use of field material to produce a grade having a desired specific elevation. Currently, the marking of specified elevations (i.e., "setting grades") requires a crew of three. One crew member operates a leveled telescopic lens or construction level, while the two other crew members carry grade stakes to predetermined locations and then drive the grade stakes into the ground under the direction of the construction level operator. The construction level operator typically communicates with the other crew members using a two-way radio or hand signals.
The marking of an elevation at a predetermined location on a construction site requires a grade stake be driven into the ground until the top surface of the stake resides at the desired elevation. The construction level operator determines the desired elevation by measuring the vertical distance between a fixed level plane (i.e., a point of known elevation) and the predetermined location. The construction level operator establishes the fixed level plane by viewing through the construction level a ruled rod having a previously leveled line of site. After establishing the fixed level plane, the measurement of the vertical distance requires the holding of the ruled rod over the predetermined location followed by the reading of the distance the predetermined location lies either above or below the known elevation. A comparison of the vertical distance to the elevation of the fixed level plane permits the determination of the elevation of the predetermined location so that the top of the grade stake may be positioned to indicate the desired elevation.
Although the above-described method of marking specified desired elevations functions satisfactorily, it is unfortunately both time consuming and labor intensive. That is especially true when the grades are set over expansive areas. For example, construction of highways stretching many miles may require four grade stakes across the road bed for every fifty feet of highway, and, because modern roads are built on several layers of compacted base material, new grades must be set at each fifty foot station for each layer. Essentially, the use of a construction level operator and several laborers wastes both time and money because the construction level operator must read the height for each grade stake, determine how far to drive each grade stake into the ground, and then instruct the laborers in the driving of the grade stake. Miscommunications often occur, and, when grade stakes are set improperly, the entire process must be repeated.
Accordingly, an apparatus that eliminates the necessity of additional laborers while ensuring the accurate setting of grade stakes will save both time and money on any construction project.